WO2022249433A1

WO2022249433A1 - Diffusion body and illumination device

Info

Publication number: WO2022249433A1
Application number: PCT/JP2021/020331
Authority: WO
Inventors: 覚岡垣; 将利西村
Original assignee: 三菱電機株式会社; 三菱電機照明株式会社
Priority date: 2021-05-28
Filing date: 2021-05-28
Publication date: 2022-12-01
Also published as: JP7325692B2; JPWO2022249433A1; EP4328481A4; CN117377849A; JP2023129712A; EP4328481A1

Abstract

A diffusion body (10) receives incoming first light (L1) and emits scattered light. The diffusion body (10) has one light-entering surface (10a) through which the first light (L1) enters in a first direction and a first light-emitting surface (10b). The light-entering surface (10a) is formed on an end face of the diffusion body (10). First emitted light (L21) is emitted from the first light-emitting surface (10b). Second emitted light (L22) is emitted from a second light-emitting surface (10c), which is a surface other than the first light-emitting surface (10b) of the diffusion body (10). The intensity of the first emitted light (L21) increases as the emitted direction of the first emitted light (L21) is closer to the first direction. The correlated color temperature of the first light (L1) is lower than the correlated color temperature of the first emitted light (L21) and is higher than the correlated color temperature of the second emitted light (L22).

Description

Diffuser and Lighting Device

The present disclosure relates to diffusers and lighting devices.

There is a proposal for a lighting device that is attached to a recess in the ceiling and has the form of a pseudo skylight (see Patent Document 1, for example). The lighting device has a lighting panel mounted in a recess in the ceiling and side walls therearound. The sidewalls have independently controllable triangular light emitting areas to mimic sun and shadow areas. The sun and shadow areas mimic the sun areas and unlit shadow areas that would be formed by the light coming through the skylight if the lighting panel were an actual skylight. .

Japanese Patent No. 6081663

However, in Patent Document 1, when an observer observes the lighting panel, the brightness and color of the lighting panel are different from natural scenery (for example, natural blue sky), so the observer feels unnatural. There is a problem of making

The present disclosure provides an observer with a natural landscape that looks as if the sunlight is shining even in an environment where the blue sky cannot be visually recognized and there is actually no sunlight. for the purpose.

A diffuser according to an aspect of the present disclosure is a diffuser that receives first light and emits light including scattered light, and includes a light incident surface on which the first light is incident in a first direction, and , and a first light exit surface, wherein the light entrance surface is formed on an end surface of the diffuser, the first exit light is emitted from the light exit surface, and the first light of the diffuser is emitted from the light exit surface. A second emitted light is emitted from a second light emitting surface other than the emitting surface, and the intensity of the first emitted light is such that the emission direction of the first emitted light approaches the first direction. The correlated color temperature of the first light is lower than the correlated color temperature of the first emitted light and higher than the correlated color temperature of the second emitted light.

According to the present disclosure, it is possible to provide the observer with a natural landscape as if the light from the sun were illuminated.

1 is a cross-sectional view showing a schematic configuration of a lighting device according to Embodiment 1; FIG. 2 is an enlarged cross-sectional view of the diffuser shown in FIG. 1; FIG. FIG. 5 is a cross-sectional view showing a schematic configuration of a lighting device according to Embodiment 2; FIG. 10 is a cross-sectional view showing an example of a schematic configuration of a lighting device according to Modification 1 of Embodiment 2; FIG. 10 is a cross-sectional view showing another example of the schematic configuration of the lighting device according to Modification 1 of Embodiment 2; FIG. 10 is a cross-sectional view showing another example of the schematic configuration of the lighting device according to Modification 1 of Embodiment 2; FIG. 10 is a cross-sectional view showing another example of the schematic configuration of the lighting device according to Modification 1 of Embodiment 2; FIG. 10 is a cross-sectional view showing a schematic configuration of a lighting device according to Modification 2 of Embodiment 2;

A diffuser and a lighting device according to embodiments of the present disclosure will be described below with reference to the drawings. The following embodiments are merely examples, and the embodiments can be combined as appropriate and each embodiment can be modified as appropriate.

In the drawing, the coordinate axes of the XYZ orthogonal coordinate system are shown to facilitate understanding of the explanation. The Y-axis direction is the normal direction of the light exit surface of the diffuser. If the light exit surface includes a curved surface, an inclined surface, or both, the Y-axis direction may be the direction indicated by the normal direction of the center of the light exit surface or the sum of the normal vectors of the light exit surface. good. When the lighting device is mounted on the ceiling, the -Y axis direction is vertically downward and the +Y axis direction is vertically upward. The X-axis direction and the Z-axis direction are directions orthogonal to the Y-axis direction. When the lighting device is mounted on the ceiling, the X-axis and Z-axis directions are horizontal. The +Z-axis direction is the traveling direction in the diffuser of the light incident from the light incident surface.

<<Embodiment 1>>
FIG. 1 is a cross-sectional view showing a schematic configuration of a lighting device 100 according to Embodiment 1. FIG. As shown in FIG. 1, lighting device 100 has diffuser 10 and light source 20 .

The light source 20 emits light L1 as first light. The light source 20 emits, for example, light L1 toward the light incident surface 10a. The light source 20 is arranged, for example, so as to face the light incident surface 10a. In addition, in the following description, the light source 20 is also called "the first light source 20".

The diffuser 10 is, for example, a plate-like member. The diffuser 10 has a light incident surface 10a and a first light exit surface 10b. The diffuser 10 guides the light L1 incident on the light incident surface 10a by total reflection, and scatters at least a part of the light L1 to be emitted from the first light emitting surface 10b (XZ plane). . In FIG. 1, the totally reflected light is denoted by L11.

The light incident surface 10a receives the light L1 emitted from the light source 20 from the Z-axis direction, which is the first direction. The light incident surface 10a is an end surface in contact with the −Z-axis direction end of the first light exit surface 10b. Thus, the light incident surface 10a is formed on the end surface of the diffuser 10 including the end portion of the first light exit surface 10b. In the example shown in FIG. 1, the diffuser 10 has one light incident surface 10a. Note that the diffuser 10 may have at least one light incident surface 10a. In other words, the light incident surface 10a may include a plurality of end faces of the diffuser 10, and the light L1 may enter each of the plurality of end faces.

An example of a specific configuration of the diffuser 10 is a light guide panel, which is a light transmissive member that diffuses light by transmitting, reflecting, and guiding the light. In this case, the light guide panel includes a transparent resin and a scattering structure that scatters incident light to generate scattered light. The scattering structures are formed by scattering particles, crystals, voids or depressions on the surface of the diffuser 10 that have a different refractive index than the diffuser 10 . In the following description, an example in which the diffuser 10 is formed of a transparent resin 11 and scattering particles 12 will be described.

FIG. 2 is an enlarged cross-sectional view of the diffuser 10 shown in FIG. As shown in FIG. 2, the diffuser 10 is made up of, for example, a transparent resin 11 that is a transparent resin member and a plurality of scattering particles 12 dispersed in the transparent resin 11 .

Next, the scattering phenomenon in the diffuser 10 will be explained. A part of the light L1 that has entered the diffuser 10 from the light incident surface 10a is scattered by the scattering particles 12 . In FIG. 2, the light generated by scattering is labeled L12. Light L12 has a dependence on the scattering angle and the wavelength of light L1. When the size of the scattering particles 12 is sufficiently small with respect to the wavelength of the light L1, the light L12 is isotropic. Therefore, the dependence on the scattering angle is small. is relatively higher than the scattering intensity when . On the other hand, when the size of the scattering particles 12 is close to the wavelength of the light L1, the degree of forward scattering is relatively greater than the degree of backward scattering. Also when the size of the scattering particles 12 is close to the wavelength of the light L1, the scattering intensity when the wavelength of the light L1 is short is relatively higher than the scattering intensity when the wavelength of the light L1 is long. .

As shown in FIG. 1, at least part of the light L1 that has entered the diffuser 10 is emitted as first emitted light L21 and second emitted light L22. The first emitted light L21 is emitted from the first light emitting surface 10b. The second emitted light L22 is emitted from the second light emitting surface 10c of the diffuser 10 other than the first light emitting surface 10b. In the example shown in FIG. 1, the second light exit surface 10c is an end surface of the diffuser 10 facing the +Z-axis direction. The second light exit surface 10c is not limited to the end face facing the +Z-axis direction, and may be at least one of the end face facing the +Y-axis direction and the end face facing the −Y-axis direction of the diffuser 10. , -Z-axis direction. In other words, the second light exit surface 10c is at least one of an end face facing the +Y-axis direction, an end face facing the -Y-axis direction, an end face facing the +Z-axis direction, and an end face facing the -Z-axis direction of the diffuser 10. It is sufficient if it includes one, and it may be configured by a combination of these end faces. Moreover, the diffuser 10 only needs to have at least one first light exit surface 10b. Therefore, the diffuser 10 may have a plurality of first light exit surfaces 10b.

In this way, the incident light L1 is multiple-scattered by the scattering particles 12, so that at least part of the light L1 is emitted from the diffuser 10 as the first emitted light L21 and the second emitted light L22. Moreover, at least part of the incident light L1 is emitted from the diffuser 10 as part of the second emitted light L22 without being scattered.

Here, as described above, when the size of the scattering particles 12 is close to the wavelength of the light L1, the scattered light L12 has an incident direction of the light L1 (in other words, an emission direction of the light L1 emitted from the light source 20). Forward scattering, which is scattering, tends to be strong. The tendency is the same even when multiple scattering occurs within the diffuser 10, so the first emitted light L21 has dependence on the angle. That is, the intensity of the first emitted light L21 increases as the emission direction of the first emitted light L21 approaches the +Z-axis direction from the normal direction (Y-axis direction) of the first light emitting surface 10b.

The scattering intensity by the scattering particles 12 when the wavelength of the light L1 is long is lower than the scattering intensity when the wavelength of the light L1 is short. Therefore, for example, when the light L1 including a wide wavelength spectrum is incident on the light incident surface 10a, the short wavelength light L1 is preferentially scattered, and the correlated color temperature of the first emitted light L21 is the correlated color of the light L1. higher than the temperature. This phenomenon is the same as the principle of generating an actual blue sky, and is effective in making the diffuser 10 visually recognizable as a blue sky for the observer. Also, the second emitted light L22 includes scattered light and non-scattered light in the incident light L1. Therefore, the correlated color temperature of the light L1 is lower than the correlated color temperature of the first emitted light L21 and higher than the correlated color temperature of the second emitted light L22.

Further, as a preferred configuration example of the diffuser 10 according to Embodiment 1, the average particle diameter of the plurality of scattering particles 12 is within the range of 10 nm to 3000 nm, and more preferably within the range of 50 nm to 2000 nm. is. Accordingly, the intensity of the first emitted light L21 increases as the emission direction of the first emitted light L21 approaches the +Z-axis direction from the normal direction (Y-axis direction) of the first light exit surface 10b.

A preferred example of the difference between the correlated color temperature of the first emitted light L21 and the correlated color temperature of the second emitted light L22 is about the same as 100K or 100K or less. Further, the emission angle of the first emission light L21 when the first emission light L21 travels in the Z-axis direction is assumed to be 0 deg, and the first emission light L21 travels in the normal direction of the first light emission surface 10b. Assume that the emission angle of the first emission light L21 at this time is 90 degrees. Here, a preferred example of the intensity ratio of the first emitted light L21 when the emission angle is 45 degrees to the intensity of the first emitted light L21 when the emission angle is 90 degrees is in the range of 1.01 times to 10 times. and more preferably in the range of 1.1 to 5 times.

Suppose that the diffuser 10 is attached to the indoor ceiling and the light source 20 is fixed near the light entrance surface 10a, and the observer observes the first light exit surface 10b in the +Y-axis direction. At this time, the observer can visually recognize the first light emitting surface 10b as the blue sky by the first emitted light L21. In addition, the oblique direction (for example, the direction of arrow V shown in FIG. 1) is the direction in which the observer approaches the incident direction of the light L1 (that is, the +Z-axis direction) from the normal direction of the first light exit surface 10b. is higher than the brightness when observing the first light exit surface 10b in the direction normal to the first light exit surface 10b (i.e., in the vertically downward direction). . Such a change in luminance of the first light exit surface 10b accompanying a change in the line of sight of the observer (hereinafter also referred to as "observation change") is a phenomenon that occurs even in a natural blue sky. Even when a person actually observes a natural blue sky, the brightness of the blue sky changes depending on the altitude and the position of the sun. That is, the diffuser 10 according to Embodiment 1 can reproduce a more natural blue sky than the conventional technique. Therefore, according to Embodiment 1, even in an environment where the blue sky cannot be visually recognized and there is actually no incoming light from the sun, a natural landscape can be created as if the incoming light from the sun were illuminated. can be given to the observer.

Further, when the observation change with respect to the first light exit surface 10b is very small, for example, when the first light exit surface 10b is observed from directly below the diffuser 10, the change in luminance on the first light exit surface 10b is is preferably small. Therefore, the intensity of the first emitted light L21 is set to be equal to or lower than the intensity of the second emitted light L22 by designing the diffusion strength of the diffuser 10 based on the size, density, etc. of the scattering particles 12 . Thereby, the diffuser 10 can reproduce a more natural blue sky.

Further, in the example shown in FIG. 1, the diffuser 10 has one light incident surface 10a, but the diffuser 10 has two or more light incident surfaces 10a. It is possible to further reduce the change in luminance on the exit surface 10b. This makes it possible to reproduce a natural blue sky as described above.

<Effect of Embodiment 1>
According to Embodiment 1 described above, the intensity of the first emitted light L21 increases as the emission direction of the first emitted light L21 approaches the +Z-axis direction, which is the incident direction of the light L1. Also, the correlated color temperature of the light L1 is lower than the correlated color temperature of the first emitted light L21 and higher than the correlated color temperature of the second emitted light L22. This makes it possible to cause a change in luminance of the first light exit surface 10b when an observation change occurs with respect to the first light exit surface 10b. The change in brightness of the first light exit surface 10b accompanying this change in observation is a phenomenon that also occurs when a person sees a natural blue sky. Therefore, even in an environment where the blue sky cannot be visually recognized and there is actually no light from the sun, it is possible to provide the observer with a natural landscape as if the light from the sun were shining. can.

Further, according to the first embodiment, the diffuser 10 includes a transparent resin 11 having a light incident surface 10a and a first light exit surface 10b, and a plurality of scattering particles 12 dispersed in the transparent resin 11. and the plurality of scattering particles 12 are arranged such that the intensity of the first emitted light L21 increases as the emission direction of the first emitted light L21 approaches the Z-axis direction, and the correlated color temperature of the light L1 increases to the first It is dispersed in the transparent resin 11 so that the correlated color temperature is lower than the correlated color temperature of the first emitted light L21 and higher than the correlated color temperature of the second emitted light L22. As a result, when a change in observation occurs with respect to the first light exit surface 10b, a change in luminance of the first light exit surface 10b can be produced, and the same phenomenon as when a person sees a natural blue sky occurs. can be made

Further, according to Embodiment 1, the intensity of the first emitted light L21 is equal to or lower than the intensity of the second emitted light L22. Accordingly, when the first light exit surface 10b is observed from directly below the diffuser 10, the change in luminance on the first light exit surface 10b is small. Therefore, the diffuser 10 can reproduce a more natural blue sky.

<<Embodiment 2>>
FIG. 3 is a cross-sectional view showing a schematic configuration of lighting device 200 according to Embodiment 2. As shown in FIG. 3, the same or corresponding components as those shown in FIG. 1 are given the same reference numerals as those shown in FIG. The illumination device 200 according to Embodiment 2 differs from the illumination device 100 according to Embodiment 1 in that it further includes a frame 30 . Except for this point, the illumination device 200 according to the second embodiment is the same as the illumination device 100 according to the first embodiment.

As shown in FIG. 3, the illumination device 200 has a diffuser 10, a light source 20, and a frame 30.

The frame 30 is arranged at the end of the diffuser 10 opposite to the light incident surface 10a. In the example shown in FIG. 3, the frame 30 is arranged at the end 10e of the diffuser 10 in the +Z-axis direction. The end portion 10e in the +Z-axis direction is the end portion of the diffuser 10 that includes the second light exit surface 10c. The frame 30 has a portion facing the plane S including the light incident surface 10a.

The frame 30 has a first portion 31 fixed to the end face 10d facing the +Y-axis direction of the +Z-axis direction end 10e of the diffuser 10, and a second portion 32 facing the plane S. and The first portion 31 extends in the Z-axis direction. The second portion 32 extends in the −Y-axis direction from the +Z-axis direction end of the first portion 31 .

The frame 30 is made of a light transmissive material or a light reflective material. The frame 30 is made of metal, resin, glass, film, or the like, for example. The frame 30 reflects, diffuses, or transmits incident light, thereby emitting the light toward the space where the observer exists. This allows the observer to perceive that the frame 30 is an area with higher luminance than the other areas of the illumination apparatus 200 when the observer observes the illumination apparatus 200 . Therefore, it is possible to provide the observer with a landscape as if the sunlight were shining into the frame 30 in the direction of the arrow A shown in FIG. Therefore, it is possible to give the observer a more natural scenery.

The light that enters the frame 30 is, for example, at least part of the light L1 emitted from the light source 20, the first emitted light L21, and the second emitted light L22. As described above, in the example shown in FIG. 3, the frame 30 is fixed to the +Z-axis direction end portion 10e of the diffuser 10 including the second light exit surface 10c. Since the second emitted light L22 is emitted from the second light emitting surface 10c, the light that enters the frame 30 is mainly the second emitted light L22. Further, another light source (not shown) different from the light source 20 may be arranged near the frame 30 . In this case, the frame 30 can make the brightness of the frame 30 higher than the brightness of the other regions of the illumination device 200 by reflecting, diffusing, transmitting, or the like the light incident from the other light source.

<Effect of Embodiment 2>
According to the second embodiment described above, similarly to the first embodiment, when a change in observation occurs with respect to the first light exit surface 10b, a change in luminance of the first light exit surface 10b is caused. be able to. The change in brightness of the first light exit surface 10b accompanying this change in observation is a phenomenon that also occurs when a person sees a natural blue sky. Therefore, even in an environment where the blue sky cannot be visually recognized and there is actually no light from the sun, it is possible to provide the observer with a natural landscape as if the light from the sun were shining. can.

Further, according to Embodiment 2, the lighting device 200 has the frame 30 arranged at the end portion 10e of the diffuser 10 opposite to the light incident surface 10a. As a result, the light emitted from the diffuser 10 (for example, the first emitted light L21, the second emitted light L22, etc.) enters the frame 30, and the luminance of the frame 30 is higher than the luminance of other regions of the illumination device 200. can be raised. Therefore, it is possible to provide the observer with a landscape as if sunlight is shining through the frame 30 . Therefore, it is possible to give the observer a more natural scenery.

<<Modification 1 of Embodiment 2>>
FIG. 4 is a cross-sectional view schematically showing an example of the configuration of a lighting device 200A according to Modification 1 of Embodiment 2. As shown in FIG. 5, 6 and 7 are cross-sectional views schematically showing other examples of the configuration of a lighting device 200A according to Modification 1 of Embodiment 2. FIG. 4 to 7, components that are the same as or correspond to those shown in FIG. 3 are labeled with the same reference numerals as those shown in FIG. Illuminating device 200A according to Modification 1 of Embodiment 2 differs from illuminating device 200 according to Embodiment 2 in terms of the placement location of frame 30A. Except for this point, the lighting device 200A according to the first modification of the second embodiment is the same as the lighting device 200 according to the second embodiment.

As shown in FIG. 4, the illumination device 200A has a diffuser 10, a light source 20, and a frame 30A.

In the example shown in FIG. 4, the frame 30A is also arranged at the end 10e of the diffuser 10 in the +Z-axis direction, like the frame 30 shown in FIG. Specifically, the frame 30A is arranged at a position facing the plane S including the light entrance surface 10a and in contact with the first light exit surface 10b. In this case also, at least part of the light L1 emitted from the light source 20, the first emitted light L21, and the second emitted light L22 enters the frame 30A. The frame 30A reflects, diffuses, and transmits incident light, thereby making the brightness of the frame 30A higher than the brightness of other regions of the illumination device 200A.

The frame 30A includes a first portion 31A fixed to the first light exit surface 10b and facing a plane S including the light entrance surface 10a, and an end portion of the first portion 31A in the -Y-axis direction. and a second portion 32A extending in the +Z-axis direction. In the example shown in FIG. 4, the angle formed by the first portion 31A and the second portion 32A is a right angle.

As shown in FIG. 5, the illumination device 200A may further have a second light source 40 arranged near the frame 30A. The second light source 40 is arranged outside the frame 30A. Specifically, the second light source 40 faces the second portion 32A of the frame 30A in the −Y-axis direction and is arranged on the +Z-axis side of the second light exit surface 10c of the diffuser 10. . The second light source 40 emits light L2 as second light. The second light source 40 has, for example, the same configuration as the first light source 20 . Note that the second light source 40 may have a configuration different from that of the first light source 20 .

In the example shown in FIG. 5, the frame 30A directs the incident light L2 from the second light source 40 to the space 110 facing the first light exit surface 10b (that is, the space where the first exit light L21 is emitted). lead. Specifically, the frame 30A reflects, diffuses, and transmits the light L2. Thereby, the brightness of the frame 30A can be made higher than the brightness of other regions of the illumination device 200A.

As shown in FIG. 6, the second light source 40 may be arranged near the end face 10d facing the +Y-axis direction on the side opposite to the first light exit face 10b of the diffuser 10. In the example shown in FIG. 6, the second light source 40 is arranged on the +Y-axis side of the end surface 10d of the diffuser 10 facing the +Y-axis direction. That is, the second light source 40 may be arranged at a position facing the end face 10d of the diffuser 10 facing the +Y-axis direction. In this case, the frame 30A reflects, diffuses, and transmits the light transmitted through the diffuser 10 out of the light L2 emitted by the second light source 40 . Thus, the frame 30A may guide at least part of the light L2 to the space 110 facing the first light exit surface 10b. Also in the example shown in FIG. 6, the brightness of the frame 30A can be made higher than the brightness of other areas of the illumination device 200A.

The shape of the frame 30A is not limited to the shapes shown in FIGS. As shown in FIG. 7, the first portion 31A of the frame 30A fixed to the first light exit surface 10b is positioned in front of the first light exit surface 10b as the distance from the first light exit surface 10b increases. You may incline with respect to the normal line of the 1st light-projection surface 10b so that space may spread.

<Effect of Modification 1 of Embodiment 2>
According to Modified Example 1 of Embodiment 2 described above, similarly to Embodiment 1 or 2, when a change in observation occurs with respect to first light exit surface 10b, the first light exit surface 10b A change in luminance can be produced. The change in brightness of the first light exit surface 10b accompanying this change in observation is a phenomenon that also occurs when a person sees a natural blue sky. Therefore, even in an environment where the blue sky cannot be visually recognized and there is actually no light from the sun, it is possible to provide the observer with a natural landscape as if the light from the sun were shining. can.

Further, according to Modification 1 of Embodiment 2, the illumination device 200A is arranged in the diffuser 10 at a position facing the plane S including the light entrance surface 10a and in contact with the first light exit surface 10b. It has a frame 30A arranged. This makes it easier for the first emitted light L21 emitted from the first light emitting surface 10b to enter the frame 30A, so that the brightness of the frame 30A can be made higher than the brightness of other regions of the illumination device 200A. Therefore, it is possible to provide the observer with a landscape as if sunlight were shining through the frame 30A. Therefore, the observer's recognition of the position of the sun is strengthened, so that a more natural scenery can be given to the observer.

Further, according to Modification 1 of Embodiment 2, illumination device 200A further includes second light source 40 that emits light L2, and frame 30A emits at least part of light L2 from the first light exit surface. lead to space 110 facing 10b. Thereby, the light L2 emitted by the second light source 40 is made incident on the frame 30A, and the incident light L2 is reflected, diffused, transmitted, etc., so that the brightness of the frame 30A is changed to the brightness of other regions of the illumination device 200A. can be made even higher.

<<Modification 2 of Embodiment 2>>
FIG. 8 is a cross-sectional view showing a schematic configuration of a lighting device 200B according to Modification 2 of Embodiment 2. As shown in FIG. 8, the same or corresponding components as those shown in FIG. 3 are given the same reference numerals as those shown in FIG. A lighting device 200B according to Modification 2 of Embodiment 2 differs from lighting device 200 according to Embodiment 2 in the configuration of frame 30B. Except for this point, the lighting device 200B according to the second modification of the second embodiment is the same as the lighting device 200 according to the second embodiment.

As shown in FIG. 8, the illumination device 200B is composed of a diffuser 10, a light source 20, and a frame 30B.

In the example shown in FIG. 8, the frame 30B is a member (frame body) that surrounds the space 110 facing the first light exit surface 10b. Note that the frame 30B may be a frame surrounding the diffuser 10 . Also, the frame 30B may be a frame surrounding both the space 110 facing the first light exit surface 10b and the diffuser 10. As shown in FIG.

The frame 30B has a bright area 51 and a dark area 52. The bright region 51 is a region with high brightness, and the dark region 52 is a region with a lower brightness than the bright region 51 . The bright region 51 and the dark region 52 are formed by providing regions having different light transmittance or light reflectance in the frame 30B. The observer can perceive the bright region 51 and the dark region 52 as sunshine and shade formed on the window frame. In other words, the observer can feel as if actual sunlight, that is, natural light is coming from the diffuser 10 in the direction of arrow A shown in FIG. Therefore, the observer can further feel that a pseudo blue sky is being reproduced by lighting device 200B.

<Effect of Modification 2 of Embodiment 2>
According to Modified Example 2 of Embodiment 2 described above, similarly to Embodiment 1 or 2, when a change in observation occurs with respect to first light exit surface 10b, the first light exit surface 10b A change in luminance can be produced. The change in brightness of the first light exit surface 10b accompanying this change in observation is a phenomenon that also occurs when a person sees a natural blue sky. Therefore, even in an environment where the blue sky cannot be visually recognized and there is actually no light from the sun, it is possible to provide the observer with a natural landscape as if the light from the sun were shining. can.

Further, according to Modification 2 of Embodiment 2, frame 30B of lighting device 200B has bright region 51 and dark region 52 . As a result, the observer can perceive the bright region 51 and the dark region 52 as sunshine and shade formed on the window frame. In other words, the observer can feel as if actual sunlight, that is, natural light is coming through the diffuser 10 . Therefore, the observer can feel that a pseudo blue sky is being reproduced by lighting device 200B.

10 diffuser 10a light incident surface 10b first light emitting surface 10c second light emitting surface 10e end 11 transparent resin 12 scattering particles 20 light source (first light source) 30, 30A, 30B frame, 40 second light source, 51 bright area, 52 dark area, 100, 200, 200A, 200B lighting device, 110 space, L1 first light, L2 second light, L21 first emitted light, L22 Second emitted light.

Claims

A diffuser that receives a first light and emits light containing scattered light,
a light incident surface on which the first light is incident in a first direction;
and a first light exit surface;
The light incident surface is formed on an end surface of the diffuser,
a first output light is emitted from the first light output surface;
a second output light is emitted from a second light output surface that is a surface other than the first light output surface of the diffuser;
The intensity of the first emitted light increases as the emission direction of the first emitted light approaches the first direction,
the correlated color temperature of the first light is lower than the correlated color temperature of the first emitted light and higher than the correlated color temperature of the second emitted light;
A diffuser characterized by:
The diffuser is
a resin member provided with the light entrance surface, the first light exit surface, and the second light exit surface;
2. The diffuser of claim 1, comprising a plurality of scattering particles dispersed within said resin member.
The average particle size of the plurality of scattering particles is in the range of 10 nm to 3000 nm.
3. The diffuser of claim 2, wherein:
The average particle size of the plurality of scattering particles is in the range of 50 nm to 2000 nm.
4. The diffuser according to claim 3, characterized in that:
the light incident surface includes a plurality of end surfaces of the diffuser;
the first light is incident on each of the plurality of end faces;
5. The diffuser according to any one of claims 1 to 4, characterized in that:
a diffuser according to any one of claims 1 to 5;
a first light source that emits the first light;
and a frame disposed at an end of the diffuser opposite to the light incident surface.
further comprising a second light source emitting a second light;
the frame guides at least part of the second light to a space facing the first light exit surface;
7. The lighting device according to claim 6, characterized in that:
The frame is a member that surrounds the space facing the first light exit surface, and has a bright area and a dark area.
7. The lighting device according to claim 6, characterized in that: